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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pablo Neira Ayuso <pablo@netfilter.org>
Subject: [PATCH 4.14 29/61] netfilter: nf_tables: disable preemption in nft_update_chain_stats()
Date:   Fri,  6 Jul 2018 07:46:53 +0200
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pablo Neira Ayuso <pablo@netfilter.org>

commit ad9d9e85072b668731f356be0a3750a3ba22a607 upstream.

This patch fixes the following splat.

[118709.054937] BUG: using smp_processor_id() in preemptible [00000000] code: test/1571
[118709.054970] caller is nft_update_chain_stats.isra.4+0x53/0x97 [nf_tables]
[118709.054980] CPU: 2 PID: 1571 Comm: test Not tainted 4.17.0-rc6+ #335
[...]
[118709.054992] Call Trace:
[118709.055011]  dump_stack+0x5f/0x86
[118709.055026]  check_preemption_disabled+0xd4/0xe4

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/netfilter/nf_tables_core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -126,15 +126,15 @@ static noinline void nft_update_chain_st
 	if (!base_chain->stats)
 		return;
 
+	local_bh_disable();
 	stats = this_cpu_ptr(rcu_dereference(base_chain->stats));
 	if (stats) {
-		local_bh_disable();
 		u64_stats_update_begin(&stats->syncp);
 		stats->pkts++;
 		stats->bytes += pkt->skb->len;
 		u64_stats_update_end(&stats->syncp);
-		local_bh_enable();
 	}
+	local_bh_enable();
 }
 
 struct nft_jumpstack {